title: Frequent occurrence of mixed Enterocytozoon bieneusi infections in humans.
abstract: Enterocytozoon bieneusi (phylum Microsporidia) is a human pathogen with a broad host range. Following the sequencing of 3.8 Mb of the estimated 6-Mb E. bieneusi genome, simple sequence repeats (micro- and minisatellites) were identified. Sequencing of four such repeats from various human and animal E. bieneusi isolates identified extensive sequence polymorphism and enabled the development of a multilocus genotyping method to study the epidemiology of this pathogen. We genotyped E. bieneusi DNA extracted from 197 fecal samples originating from children with diarrhea who were residing in Kampala, Uganda. Three newly identified microsatellite markers and the internal transcribed spacer were PCR amplified, and multiple cloned amplicons for each marker were sequenced from each individual. Most microsatellite sequences were unique to the Ugandan population. Significantly, polymorphism not only was present among isolates but was also found within isolates. This observation suggests that infections with heterogeneous E. bieneusi populations are common in this region. However, the data do not exclude that some of the polymorphism originates from divergent paralogs within the genome. The frequent occurrence of multiple sequences within an isolate precluded the identification of multilocus genotypes. This observation raises the possibility that in a region in which the prevalence of E. bieneusi is high, sequencing of uncloned PCR products may not be adequate for multilocus genotyping.
authors.affiliation: Department of Infectious Disease and Global Health, Tufts Cummings School of Veterinary Medicine, North Grafton, Massachusetts, USA.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Widmer
authors.forename: Julia
authors.initials: J
authors.lastname: Dilo
authors.forename: James K
authors.initials: JK
authors.lastname: Tumwine
authors.forename: Saul
authors.initials: S
authors.lastname: Tzipori
authors.forename: Donna E
authors.initials: DE
authors.lastname: Akiyoshi
mesh_terms: D016000:Cluster Analysis; D060085:Coinfection / Q000453:epidemiology* / Q000382:microbiology*; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D021862:Enterocytozoon / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D018895:Microsatellite Repeats; D016881:Microsporidiosis / Q000453:epidemiology* / Q000382:microbiology*; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D016133:Polymerase Chain Reaction; D015995:Prevalence; D014454:Uganda / Q000453:epidemiology
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer